I'm using a Maxilink ML629 to try and fault find a P2476C Particulate Matter sensor temperature circuit error.

Sometimes when I link the Autel to the BMW, scan and look at complete list there is only 1 Exhaust Gas Temperature listed, and it shows the correct value eg EGT1-1 46.40

However sometimes when I connect the unit there are 3 readings present, and the values do not look correct.

EGT1-1  -39.46F

EGT1-2 4061..66F

EGT1-3 1342.76F

How come when EGT1-1 is the only reading for exhaust gas temperatures does it read correctly, and when the 3 readings are listed I'm getting an open-circuit (-40F) of EGT1-1 and readings of over 6,700F (3,700C)  on EGT1-2 and EGT1-3

I've unplugged the 2 temperature sensors on the DPF and these register as EGT1-2 and EGT1-3. Both drop to -40F (open circuit) when unplugged looking at the live data.

I'm going around in circles trying to find out which sensor is generating the error code. Any help would be gratefully received. 

There are 3 temperature sensors on the exhaust, and I think also possibly temperature sensors inside the O2/lambada sensors. Do you know which one you would go for? I think I've eliminated the 3 temperature sensors so I am leaning towards one (possibly the second) O2 sensors located just after the DPF.

Thank you